My previous research in epigenetics and clinical training as a rheumatology fellow have prepared me well for a future career as a physician scientist. The K08 proposal described herein will allow me the necessary protected time and mentoring to expand my skills and achieve my primary goals of becoming leader in the field of osteoarthritis (OA) epigenetics. I will participate in formal coursework with a particular focus on bioinformatics, statistics, and research communication at the University of Oklahoma Health Sciences Center. I will expand my presentation skills through both didactic training and presentation of my research findings. My career development will be greatly advanced by my appointment as an Oklahoma Shared Clinical and Translational Resources Scholar, as well as regular meetings with my primary mentor and advisory committee. My research during this pivotal period will focus on OA, a chronic, debilitating musculoskeletal disease affecting 40% of US adults over the age of 70. Understanding the mechanisms of gene-environmental interaction and the contributions of extraarticular tissues to OA are key to the development of clinical biomarkers and therapeutic agents. I have published data showing significantly altered DNA methylation patterns in OA cartilage and subchondral bone, and have preliminary data from peripheral blood mononuclear cells of OA patients demonstrating remarkably consistent epigenetic dysregulation of several immune-related pathways. Based on these data, I hypothesize that OA is a disease characterized by low-level systemic inflammation, associated with dysregulated epigenomes that alter gene transcription, leading to disease pathogenesis. To evaluate this, I will recruit knee OA patients at risk of radiographic progression and perform serial blood draws and knee X-rays for later analysis. I will determine if changes in circulating inflammatory cell populations and/or their response to stimulation are present in knee OA patients compared to both healthy and rheumatoid arthritis controls (Aim 1), and examine whether patterns in inflammatory cell composition are predictive of radiographic OA progression over time, using state-of-the-art cyTOF analysis. I will then confirm an altered DNA methylation pattern using banked DNA from a large OA cohort (Aim 2a). Subsequently, I will study DNA methylation and gene transcription in leukocyte subsets: CD4+, CD8+, and monocyte cells (Aim 2b). Finally, I will use a novel, targetable dCas9-TET1 fusion protein to evaluate the functional consequences of specific DNA demethylation events I previously identified in my OA cartilage work (Aim 3). Discoveries achieved by these aims will form the preliminary data for strong R01 applications to confirm novel diagnostic biomarkers and develop new therapeutic strategies to treat this devastating disease. If successful, I will provide the first data regarding circulating OA inflammatory cell subpopulations. Leveraging the core facilities at OMRF, I will additionally provide a publically-available biorepository of the specimens and data I collect for future study.